Enclosed arc lamp



April 4, 1939.

c. w. JAMESON ENCLOSED ARC LAMP Filed June 28, 1957 2 Sheets-Sheet 1 7 1320611221" enceWJa/vzes'm |ll|||llllllll 1 III III I ll n q April 4, 1939. c. W.ICJAI)VIESON 2,152,763

ENCLOSED ARC LAMP Filed June 28, 1937 2 Sheets-Sheet 2 Ha J. M325 Patented Apr. 4, 1939 ENCLOSED ARC LAMP Clarence W. Jameson, Lombard, 111., assignor to Atlas-Ometer 00., Chicago, Ill., a corporation of Illinois Application June 28, 1937,. Serial No. 150,675

8 Claims.

The electric arc struckbetween carbon electrodes is used very extensively in scientific and industrial fields, such as the irradiation of foods, medicines and the like, and the testing of color for fastness to light, because of its eificiency and effectiveness as a constant source of ultraviolet and other actinic rays.

My invention is applicable to the so-called enclosed arc type in which the arc is surrounded by a transparent enclosure for the purpose of restricting the admission of oxygen to the arc and maintainingan atmosphere of gas surrounding the arc, not conducive to the consumption of the electrodes. Such enclosures are generally of glass, quartz, or other suitable material, capable of transmitting the desired actinic rays of the arc.

The enclosed arc is desirable in scientific fields and for the special purposes above referred to, because of. its economy of electrode consumption and especially the constancy of the are, but certain types of carbons, such as the so-c'alled cored or flame carbons, cannot be utilized in the enclosed arc type of lamp, due to the fact that, since they contain other materials besides pure carbon, the products of combustion in the form of ash or residue in powdery or film-flake condition released from the are as the carbons are consumed, is quite substantial in quantity and deposits as a film or coating upon the inside surfaces of the enclosure. This coating or film, within a short time after the arc is started, becomes increasingly dense and acts as! a filter to the ultraviolet or actinic rays from the arc, with the result that it destroys the constancy of the are as a source of ultraviolet or actinic rays.

One of the objects of my invention is to maintain the constancy of the enclosure to the transmission of actinic radiation in enclosed arc lamps employing cored or impregnated electrodes as the source of light.

A further object of my invention is toprovide an arc lamp of the enclosed arc type, in which the surfaces of the enclosure through which the actinic rays are transmitted will be maintained free and clear of any coating or film.

Other objects of my invention will appear hereinafter.

In the accompanying drawings, I have illustrated two forms of enclosed are types of lamp in which my invention is embodied.

Fig. 1 illustrates in elevation and partly in section an enclosed arc lamp of the vertical type, in which the carbon electrodes are disposed in vertical alignment for horizontal direction of the Fig. 2 is a transverse section on the line 22 of Fig. 1;

Figs. 3 and 4 are detailed sections of two forms of scraper blades or cleaning devices;

Fig. 5 is a vertical section on the line 5-5 of Fig. 6, illustrating another form of, lamp mechanism, particularly the arc enclosure portions thereof, in which the carbon electrodes are dis posed in alignment horizontally, so that the rays can be directed downwardly; and

Fig. 6 is a vertical section on the line 6--6 of the structure shown in Fig. 5.

Referring first to Figs. 1 to 4, inclusive, the electromagnetic mechanism A, which controls the upper electrode, is indicated sufiiciently to be representative of any suitable control mechanism well known in arc lamp construction. This mechanism usually has a slip clutch l which grips the upper carbon electrode 2 to strike the arc initially by contacting the upper electrode 2 with the lower electrode 3, and to control the feeding of the upper electrode toward the lower one as the carbons consume during operation, all in a well known manner. The are indicated at i is established between the ends of the upper and lower electrodes 2 and 3. V

The enclosure for the arc, indicated generally as C, is. arranged to enclose the arc and the portions of the electrodes which are consumed during operation. In the present instance, this enclosure is in the form of a transparent cylindrical globe member D positioned between an upper circular plate E and a lower circular plate F. The transparent cylinder D is of glass, quartz, or Corex-D, generally used for this purpose because of its ultraviolet or transmitting qualities.

.The upper and lower ends of the cylinder walls are accurately ground and bear against accurately machined surfaces on the upper and lower plates E and F, in order to insure a tight jointtherebetween. The lower portion of Fig. 1 shows in section the lower end 5 bearing against the machined surface 6 of the lower plate F, this same construction being duplicated for the upper plate and upper end of the cylinder. wall. This assembly is yieldingly held together by means of, the rods 1, two of which are provided, which extend between the upper and lower plates. The upper ends of the rods are permanently secured to ears 8 projecting from the edge of the plate by means of the nuts 9. The lower ends of these rods extend freely through holes in corresponding ears ill of the lower plate and carry wing nuts I I. Between the wing nuts and the ears spiral springs l2 are provided to yieldingly clamp the cylinder between the upper and lower plates. This also makes the lower plate and cylinder readily removable when it is desired to gain access to the interior of the enclosure for the purpose of trimming the lamp by replacing the carbons,

The lower carbon electrode 3 is supported in position by a pair of rods I5, the upper ends of which are secured to the upper plate E, and the lower ends of which are converged toward each other and carry a holder I6 for the carbon. The upper carbon electrode extends through an opening I! in the upper plate so that it can be moved toward and from thelower electrode and fed downwardly by the operating mechanism as it is consumed. Generally, there is provided in association with the opening I! a gas checkv be described.

Within the cylinder I provide means for main- 1 taining the interior surface of the enclosure cylinwall during the operation of the are.

der clear of ash or products of combustion which would otherwise be deposited on this surface. In the present structure this cleaning device is inthe form of two diametrically opposed scraper blades 20 positioned vertically adjacent the inner wall surface of the enclosure globe and adapted to be moved with respect to the surface so as to scrape the ash or residue deposited upon the These blades are moved with sufiicient rapidity so that no appreciable amount of ash will remainupon the surface at any time.

In the present structure, the blades are pivotally attached to and mounted on arms 2| at about midway the length of the blades whereby to equalize the pressure throughout their length. The lower ends of the arms are pivotally connected at 22 to a plate member 23, and the arms are acted upon by springs 24 to yieldingly maintain the scraper blades in contact with the surface of the cylinder with sufficient pressure to render them effective for cleaning. The carrier plate 23is mounted on the upper end of the shaft 25 which is mounted in a suitable bearing 26 in the lower plate F, and rotary motion is imparted to the carrier plate and thence to the cleaner blades 20 by means of a small electric motor 21 and a train of worm gearing,'the worm gear 28 of which is mounted on the lower end of the shaft 25 and the worm 29 of which is on the motor shaft. The motor and gearing arle shown conventionally and serve to represent any suitable means for impartingmovement to the scraper blades.

Since in an arc lamp relatively intense heat is developed and the ash or residue is dry and powdery or flaky, it is necessary to provide a blade construction suitable to meet these condi tions. Figs. 3 and 4 illustrate in detail two forms of cleaning blades which have been found suit= able for the purpose. In Fig. 3 a sheet or strip of hard-pressed asbestos or mica 30 is used. This material is clamped between metal strips 3| and the whole structure clamped adjacent its inner edges by a backing member 32. The edge 33 of the mica or asbestos strip bears against the surface of the cylinder wall, and the metal strips 3| are such as to permit a slight resiliency inthe structure to allow for possible slight irregularities in the wall of the cylinder. The metal strips 3| have slots 34 (Fig. 1) at intervals to provide the proper degree of resiliency. The blades, as shown more clearly in Fig. 2, are mounted on the arms 2| at an angle to the surface of the cylinder, the blades projecting preferably in the direction of rotation indicated by the arrow (Fig. 2), so that the cleaning edge 33 will be effective to dislodge the deposited ash and maintain the surface entirely clean. Fig. 4 illustrates a cleaning blade in the form of a thin, flexible metal strip 35, mounted in the backing member 32 and hav- 'ing a very sharp edge 36 bearing against the surface of the cylinder.

Figs. and 6 illustrate an enclosed arc type of lamp'in which the carbon electrodes 40 are disposed in horizontal alignment so that 'the rays can be utilized more effectively in a downward direction and in which the enclosure has only its bottom wall 4| of glass, quartz, or other material which will transmit the radiation.

The rest of the enclosure, consisting of four side walls 42 and a topwall 43, is arranged in the form of a housing to enclose thearc, and is preferably made of metal or other suitable opaque material. The carbon electrodes 40 are illustrated conventionally and extend through suitable openings 44 in the opposed side walls of the housing. No operating or control mechanism for the electrodes is shown, since it is understood that this may be of any suitable design well known in the art.

In order to maintain the interior surface of the bottom wall 4| of the enclosure free of ash or other products of combustion from the arc, a scraper blade 46 is mounted upon a shaft 41 with its scraping edge 48 bearing upon the interior surface of the glass wall 4| and adapted to be reciprocated across the surface from one side to the other of the enclosure. A spiral spring on the shaft 41 isconnected to the scraping blade and yieldingly urges it downward to maintain its cleaning edge in contact with the surface at the right pressure. Means for reciprocating the cleaning blade includes two telescoping arms 49, the lower ends of which carry the shaft 47, and the upper ends of which are mounted'upon a shaft 50 having bearings 5| in the walls of the enclosure. These telescoping arms 49 consist each of a tubular portionand a rod 52 extending into the tubular portion. A spiral spring 53 within the tubular portion yieldingly urges the rod member outwardly. These arms are eX- tensible and contractible in this manner to adapt the lower ends to follow the straight line of the surface as the arms-are swung in an arc about the upper shaft 50 as a center.

The shaft 50 extends through the enclosure wall and carries an arm 54 which is pivotally connected to a link 55, one end of which is connected to a crank 56 mounted in a suitable bracket 51 on the enclosure wall. This crankis driven through a train of reducing gears '58, 59-59 and 63, the latter being mounted on the shaft of a small electric motor suitably mounted on the wall of the enclosure. As the crank is slowly rotated by the motor and gears, it imparts a slow, reciprocatory movement to the shaft 50, which, through the arms 49, carries the blade across the surface of the glass wall 4|. The shaft 41 which carries the blade has small rollers 6| at its ends to facilitate the travel of the lower end of the blade-carrying frame. The lower wall 4| may, if desired, be mounted in a frame hinged at 62 so that access may be gained conveniently to the interior of the enclosure for trimming the lamp. At its opposite edge a fastening latch 63 is provided.

The arc lamp structures which have been illustrated and described are intended to be representative of an enclosed arc type of lamp suitable for the purpose, and I do not wish to be limited to the specific form thus illustrated and described. It will be obvious to one skilled in the art that changes may be made in the structure without departing from the spirit and scope of the invention as defined by the appended claims.

I claim:

1. The combination of an electric arc lamp of theclass described, including electrodes .and an enclosure for the are for transmitting actinic rays from the arc, and means operable from the exterior of said enclosure for maintaining the interior surface of said enclosure substantially free from the products of combustion of the electrodes during operation.

2. The combination of an electric arc lampof the class described, including electrodes and an actinic ray-transmitting enclosure surrounding the arc, and means Within the enclosure movable in contact with the interior surface thereof for removing therefrom the residue material resulting from combustion of said electrodes during operation of the arc.

3. In an arc lamp for the production of actinic rays, the combination of electrodes and means controlling said electrodes, an enclosure for the arc having an actinic ray-transmitting portion, means acting on the interior surface of said enclosure for preventing the accumulation of ash or other products of combustion from the are on the transmitting portion of said enclosure, and an actuating mechanism exterior of the enclosure and connected with said means.

4. In an arc lamp for the production of actinic rays, the combination of electrodes and means controlling said electrodes, an enclosure for the are having an actinic ray-transmitting portion, a surface-cleaning device acting on the interior surface of said ray-transmitting portion of said enclosure to remove therefrom the residue products of combustion from the arc, and means for actuating said cleaning device.

5. In an arc lamp for the production of actinic rays, the combination of electrodes and means controlling said electrodes, an enclosure for the are having an actinic ray-transmitting portion, a scraper device adapted to be moved along the interior surface of the ray-transmitting portion of the enclosure to remove therefrom the residue resulting from combustion of the electrodes, and means for actuating said scraper device.

6. -In an arc lamp of the enclosed arc type, the combination of electrodes, an enclosure for the are including a portion for the transmission of ultraviolet rays from the arc, means for maintaining said ray-transmitting portion of said enclosure substantially free from the products of combustion from the arc, including a cleaning device bearing upon the interior surface of said portion, and motor driven means for actuating said cleaning device.

'7. In an arc lamp of the enclosed arc type, the combination of electrodes, an enclosure for the are including a portion for the transmission of ultraviolet rays from the arc, means for maintaining said ray-transmitting portion of said enclosure substantially free from the products of combustion from the arc, including a scraper blade positioned within said enclosure, means for yieldingly pressing said blade against the interior surface of said ray-transmitting portion, and means for moving said blade along said surface.

8. In an arc lamp of the enclosed arc type, the combination of electrodes, an enclosure for the are including a portion for the transmission of ultraviolet rays from the arc, means for maintaining said ray-transmitting portion of said enclosure substantially free from the products of combustion from the arc, including a scraper blade positioned within said enclosure and having a scraping edge bearing against the interior surface of said ray-transmitting portion at an angle thereto, a carrier within the enclosure for said blade, means for yieldingly pressing the scraper edge of the blade against said surface, and motor driven mechanism exterior of the enclosure for actuating said carrier.

CLARENCE W. JAMESION. 

